The organic light-emitting diode (OLED) display technology, as a novel flat panel display technology, has drawn increasing attention due to advantages of active emission, high brightness, wide view angle, quick response, low energy consumption, flexibility, etc., and has become a next generation of display technology that may substitute the liquid crystal display technology.
The existing OLED display panel contains an organic material layer that is quite sensitive to moisture and oxygen, and as a result, the service life of the OLED display panel is greatly reduced. In order to solve this problem, in the prior art, the organic material layer in the OLED display panel is isolated from the outside by using various kinds of material, so that the seal performance reaches the following standards: the amount of moisture penetrated into the OLED display panel is less than 10−6 g/m2/day and the amount of oxygen penetrated is less than 10−3 cm3/m2/day. A sealing method usually includes the following steps of: in nitrogen atmosphere, placing a first substrate of the OLED display panel (this substrate is generally known as a packaging cover plate) on a base, and filling frit in a packaging region of the first substrate; aligning the second substrate with the first substrate to form a cell, and then heating the frit by a laser beam to melt the frit so that the molten frit forms a tight packaging connection between the first substrate and the second substrate.
At present, filling the frit in the packaging region of the packaging cover plate is usually done by means of thin film screen printing, as shown in FIG. 1. Specifically, a white glass plate is placed on a base (both the white glass plate and the base are not shown in the figures) first, and then the white glass plate and the thin film screen 12 are mechanically aligned with each other (with a spacing therebetween). Then, the frit 14 on the thin film screen 12 is printed onto the white glass plate by a scrapper 13, and the position of the frit 14 on the white glass plate is recorded. Next, a packaging cover plate 11 is prepared, and the position of the packaging region of the packaging cover plate 11 is aligned with the position of the frit 14 on the white glass plate recorded previously. That is, the packaging cover plate 11 is aligned with the thin film screen 12. Finally, the frit 14 on the thin film screen 12 is printed onto the packaging cover plate 11 by the scrapper 13.
However, the inventor finds that there are at least following problems in the prior art. Although the position of the packaging region of the packaging cover plate 11 is mechanically aligned with the position of the frit 14 on the white glass plate, deformation of the thin film screen 12 will inevitably occur with the increasing times of use of the thin film screen 12. In this case, the position of the frit 14 printed onto the packaging cover plate 11 through the thin film screen 12 will not be accurate. Furthermore, as the frit 14 has unsmooth lines due to the deformation of the thin film screen 12, burrs occur, and the packaging effect is influenced.